1. Field of the Invention
The present invention relates to an apparatus and method for controlling uplink transmission power in a mobile communication system. More particularly, the present invention relates to controlling uplink transmission power by compensating for the difference between a downlink path loss and an uplink path loss in a mobile communication system.
2. Description of the Related Art
To increase system capacity and improve service quality, a mobile communication system adopts downlink and uplink transmission power control schemes. However, the uplink transmission power control scheme of current mobile communication systems was designed with no regard to the disparity between a downlink path loss and an uplink path loss. This means that the conventional uplink transmission power control scheme is based on the premise of the same downlink and uplink path loss.
A mobile communication system such as a Frequency Division Duplexing (FDD) communication system may operate in different operation frequency bands, or a downlink gain may be different from an uplink gain in an area managed by a repeater. The FDD communication system may be, for example, an Institute of Electrical and Electronics Engineers (IEEE) 802.16m communication system based on Orthogonal Frequency Division Multiple Access (OFDMA).
Despite the possibility of different downlink and uplink path losses in case of different operation frequency bands or in case of different downlink and uplink gains, the conventional uplink transmission power control scheme was designed on the assumption that the downlink path loss is equal to the uplink path loss. Accordingly, if the downlink path loss is different from the uplink path loss, uplink transmission power control is not effective.